Many known constructed armor plates dissipate the impact energy of a hitting projectile on a large area of an external layer of the armor plate. Therefore, inner layers of the armor plate absorb a smaller amount of energy per area unit and thus, for example, may capture the projectile. The external layer of the armor plate may usually include a stiffen material such as a ceramic plate or a high strength metallic plate.
The existing threats for small targets like man or light vehicles are diverse and complicated. One of the known threats is the Belgium made SS109 bullet. The SS109 is a type of projectiles which uses a compound core with a lead base, and which comprises a hard steel penetrator top with a minimum hardness of 60 HRC, all covered by a copper alloy jacket. The bullet SS109, after leaving the rifle barrel, can reach a velocity of up to 910-975 m/s (depending on the gunpowder) and is equivalent to U.S. Military bullet M855.
Using steel plates for protective purposes may lead to a serious problem of added weight, for example, on light vehicles, which may limit their mobility and shorten its lifetime while increasing the Lifecycle Cost. The large weight of these steel plates may make it impossible to use those plates for personal protection.
Light-weight high-strength fabrics have been developed for armor vests. The lightest and strongest of these materials are Ultra High Weight Molecular Polyethylene (UHWMPE) materials, such as the Spectra® fiber of Honeywell and the Dyneema® fiber of DSM. However, in order to withstand direct stabbing with sharp objects like knives and high velocity penetrators such as a bullet, the UHWMPE armor plates should usually include ceramic or metallic stiffen materials, which make the production of those plates very expensive and/or make those plates too heavy.
Therefore, there is need for armor plates which may provide protection against high velocity penetrators such as small caliber ammunition, for example, with diameter of 5.56 up to 25 mm. These bullets may have high velocity impact, such as more than 870 m/s. Therefore, these bullets may have a great amount of kinetic energy, enabling the bullets to penetrate deeply into a target body. For example, a steel bullet with an impact velocity of 1000 m/s, with diameter of 7.11 mm and weight of 20.4 g, may have a penetration depth into an homogeneous steel plate of up to 45 mm and into an aluminum plate of up to 150 mm.
It will be appreciated that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. Further, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements.